The present invention relates generally to a method and apparatus for producing dental restorations using CAM/CAD procedures.
A number of methods involving the production of dental restorations and prosthetic devices are known in the art. Generally, a tooth is drilled to remove one or more defects. An impression is taken of the tooth and surrounding teeth. A master model is then created from the impression by pouring a gypsum die material into the cured impression and allowing it to harden. A wax pattern with a sprue is prepared on the die, hardened, removed from the die and invested in a refractory material. The wax is then xe2x80x9cburned outxe2x80x9d and a refractory pattern is created into which a metal or ceramic material is then cast to provide the desired dental restorative material.
Alternatively, if the lost wax process is not used, a working or duplicate die must be prepared from the original impression or from a duplicate impression made from the master model, both processes involving pouring a refractory into the impression to create the die. Metal or ceramic material is then built onto the die and the die with the material thereon is sintered to provide the dental restoration.
The above procedures are time consuming and often costly due to laboratory fees. Computer assisted design and milling machines have been introduced in the industry and are starting to make an impact. Although many of the above-mentioned steps may be reduced with the computer assisted tools, there remains a need to further simplify the processes. U.S. Pat. No. 5,690,490 is directed to a method and apparatus for fabrication of a dental restoration by pinhead molding. The method requires that impressions be taken and placed in a laser scanning box, wherein laser scanning is conducted within a controlled environment. The process is time consuming in that it requires two sets of impressions to be taken and thereafter scanned.
It is desirable that dental restorations be formed from images taken directly from the mouth. It is preferable that the restorations duplicate the original shape of the restored tooth as closely as possible.
These and other objects and advantages are accomplished by a method of producing dental restorations for teeth that need to be restored. In the process, a first set of data points is retrieved from a tooth or an image of the tooth to be restored. The tooth is prepared by the dentist and a second set of data points is retrieved from the tooth or an image of the tooth. The second set of points is compared to the first set of points to obtain a third set of points. The dental restoration is milled from dental material based on the image resulting from the third set of data points.
In an apparatus herein, a scanning device such as a probe is provided to scan the tooth or teeth in the patient""s mouth or an image produced from the tooth or teeth in the patient""s mouth to provide data that represents the scanned teeth. The apparatus further includes a mechanism for comparing two sets of data from the scanning device and calculating a third set of data. The apparatus may include a machining device or the machining device may be a separate device. The machining device reads and interprets the third set of data and mills dental material, such as metal or ceramic material, into a dental restoration representative of the image provided from the third set of data points.
The apparatus produces a three-dimensional body that is a dental restoration such as an orthodontic appliance, bridge, space maintainer, tooth replacement appliance, splint, crown, partial crown, denture, post, tooth, jacket, inlay, onlay, facing, veneer, facet, implant, abutment, cylinder, or connector.